Seam detector



R. D. JOY

SEAM DETECTOR Aug. 18, 1959 Filed March 4, 1957 Un w at Pfit fl O SEAM DETECTOR Application March 4, 1957, Serial No. 643,596

14 Claims. (Cl. 200'-81) The present invention relates to a control device for controlling an operation on a traveling length of cloth, and, more particularly, the invention relates to a control device adapted to detect the arrival of a seam in a traveling length of cloth at a station where an operation is being performed upon the cloth and for thereupon controlling said operation.

In the finishing of cloth it is common practice to sew together a number of cuts or lengths of cloth for passage through the machine performing a finishing operation, such as shearing or other finishing operations. In many cases the seam must he jumped, as in a shearing operation, to prevent cutting or tearing of the cloth or damaging of rubber rolls, for example.

' An object of the present invention is to provide a controlling device which will detect the approach of a seam to the station at which an operation is being performed on the cloth. Another object is to provide such a seam detecting device which will operate to control the operation on the cloth despite irregularities in the porosity of the cloth, .size of seam thread, decorations, lint, etc.

A further object is to provide such a seam detecting device which is readily adjustable to function with cloth of different thickness or densities.

' Another object is to provide a device of this character which is simple and inexpensive yet reliable in operation.

Other and further objects, features and advantages of the invention will become apparent as the description proceeds. i L. The device of my'invention is in the nature of an attachment which may be-applied to existing machines. Ordinarily it will be located just in advance, i.e., on the cloth approach side, of the shearing device, rolls or other mechanism which is tobe controlled.

, Inaccordance with the invention I provide means for 'unbalancing the air pressure on the opposite faces of the traveling length of cloth, herein for convenience referred I to as a; traveling Web. Air thus is constrained to flow through the cloth and the arrival of abutt seam will bring about a'sudden increase in the rate of such air flow. I jprovide means responsive to such increase in the rate of air flow through the cloth for controlling the shearing mechanism, rolls or other devices which are to be con trolledto accommodate the passage of the seam. In its preferred form such means comprises a normally-open switch which is operated by the change in pressure to open or close an electrical circuit which performs the desired control. be brought about by directing a stream of air (or other gas) against one face of the cloth or by applying a subatm ospheric pressure to one face of the cloth. The control means may be directly responsive to variations in this elevated or sub-atmospheric pressure or it may be "responsive to change in the pressure on the other face of the cloth, in each case due to the arrival of a seam. I alse provide means for continuously regulating said unbalance in air'pressure to accommodate changes in porosity ofthe cloth in the traveling web due, e.g., to difier- The unbalancing of air pressure may 4 2,900,468 Patented Aug. 18, 19 59 ences in cloth thickness or cloth density. Such means is continuously responsive to minor variation in the rate of air flow through the cloth, i.e., variation of insufficient magnitude to operate the machine control means.

In the accompanying drawing Fig. 1 is an elevation, partly broken away, of a selected embodiment of my invention;

Fig. 2 is a vertical cross section on the line 22 of Fig. 1;

Fig. 3 is a perspective view of a web of cloth, showing a butt seam therein;

Fig. 4 is a vertical mid-section of the pressure responsive control switch of the device of Fig. 1;

Fig. 5 is a vertical mid-section of the pressure-sensitive pressure-regulating valve of the device of Fig. 1;

Fig. 6 is an elevation, partly in vertical section, of a modification;

Fig. 7 is a vertical section on line 77 of Fig. 6;

Fig. 8 is an elevation, partly in vertical section, of a further modification, employing sub-atmospheric pressure, and,

Fig. 9 is a vertical mid-section of the pressure-responsive control switch of the device of Fig. 8.

Referring to the drawings, my device is positioned adjacent to the traveling web of cloth 2 comprising usually several pieces of cloth sewn together. Referring to Figs. 1, 2, 3, 4 and 5, the cloth 2, as appears particularly in Fig. 3, is provided at spaced positions along its length with butt scams 4 formed by loosely sewing the leading end of one length of cloth to the trailing end of the preceding length of cloth by stitching 6. Customarily the cloth is not lapped at the seams and the web more freely permits passage of air therethrough at a seam than elsewhere.

Referring to Figs. 1 and 2, I provide a delivery nozzle 8 in a delivery pipe it) and positioned with its discharge opening closely adjacent to but spaced from one face of the traveling web, i.e., the lower face in Fig. l. The delivery pipe 16 is connected to an air supply pipe 12 of the air supplied at 12. As shown, this valve is a needle valve which is adjusted by manual adjustment of the knob 16 to raise or lower the pressure of the air furnished to delivery pipe 10 from the pipe 12.

From pressure adjusting valve 14 the air is conveyed to the delivery pipe 10 through a 'i" 18.

Positioned directly above the delivery nozzle 8 and on the opposite upper side of the traveling web 2 is a recovery nozzle 20 (Figs. 1 and 2) carried at the end of a recovery pipe 22. The recovery pipe is supported on the delivery pipe 10 in any convenient manner, for example, by the adjustable bracket 24 provided with four set screws 26 by means of which each of the pipes 10 and 22 may be secured in the desired longitudinally adjusted position within the bracket 24. As the recovery nozzle 20 is located adjacent the face of the cloth directly opposite the delivery nozzle 8 the pressure within the recovery pipe 22 varies with changes in the rate of fiow of air through the cloth from the delivery nozzle 8 to the recovery nozzle 22.

The recovery pipe 22 is at its other end connected through a T 28 to the pressure responsive control switch 30 shown in more detail in Fig. 4. This switch comprises a 2-part housing 32 containing a flexible diaphragm 34. A switch contact rod 36 extends into the diaphragm housing through a guide block 33 mounted on the housing. The rod 36 carries at its lower end a foot 49 resting on the upper face of the diaphragm. A spring 42 biases the rod 36 downwardly so that the foot 40 continually rests upon and follows the movements of the diaphragm 34. An electrical contact 43 is supported, on a bracket QB 44, by an insulating block 46. The insulating block 46 is carried on the guide block 33. This contact 43 is spaced just above the upper end of the contact rod 36, providing a normally open switch in a circuit one side of which is the contact 43 and the other side of which is the framework of the machine. An increase of pressure within the recovery pipe 22 thus will raise the diaphragm 34, lifting the rod 36 into contact with the contact 43 and closing the circuit. The circuit is arranged in any convenient manner to effect the desired control, for example, as an energizing circuit for a relay which in turn activates a solenoid or motor which moves blades or rolls away from the seam as it travels by.

Connected to the upper end of T 18 is a pressuresensitive pressure regulating valve 58 shown in more detail in Fig. 5. This pressure-regulating valve is adapted to relieve air pressure in the supply pipe 18 in accordance with variation of the air pressure in the recovery pipe 22, to compensate for open weave or thin cloth, etc. For this purpose the recovery pipe 22 is connected through T 52 and pipe 54 to the control side of the pressure regulating valve.

The pressure regulating valve 58 has its inlet connected through pipe 56 to the T 18, which is in communication with delivery pipe 16, and its outlet 58 vented to atmos phere. Referring to Fig. 5, the pressure regulating valve 50 is in the form of a relief valve having a Z-part housing 60 containing a flexible diaphragm 62. The valve inlet port 64 is in communication with the valve outlet port 66 through a conical valve chamber 68. Within the valve chamber a valve plug 78 carried on the end of valve stem 72 is adapted upon movement to the right, as seen in Fig. 5, to increase the effective cross sectional area of the valve chamber 68 and upon movement to the left to correspondingly decrease the effective cross sectional area of the valve chamber. The stem 72 has at its other end a foot 74 lying against and held in contact with diaphragm 62 by means of a compression spring 76 so that movement of diaphragm 62, in response to changes in pressure at the control port 78 of the valve, moves the stem 72 and with it the plug 70 to correspondingly vary the effective size of the passageway through the valve.

To prevent undue collection of lint in the recovery nozzle 20, I provide a restricted passageway from supply pipe to the recovery pipe 22, to maintain the pressure within the recovery nozzle 20 normally slightly above atmospheric pressure. Referring to Fig. 1 a T 80 is provided closely adjacent to the T 18 and connecting T 18 to the delivery pipe 10. In the side arm of T 80 is threaded a plug 82 containing a small orifice 84 drilled therethrough. The orifice in the plug 82 is connected through a pipe 86 into the T 52 which connects the recovery pipe 22 and the pipe 54.

In the operation of the device so far described, the cloth web 2 passes continuously between the delivery nozzle 8 and the recovery nozzle 20. A source of air under pressure supplied at 12 passes through the supply pipe 10 and out of the nozzle 8 as a stream directed against the under face of the traveling web. Some part of the air stream passes through the cloth, causing slight elevation of pressure at the recovery nozzle 20 and in recovery pipe 22, the lower half of the diaphragm housing 32, and at the port 78 of the pressure regulating valve 50. In accordance with fluctuations of this pressure due to variations in the porosity or thickness of the cloth, etc., movement of the diaphragm 62 of the pressure regulating valve 50 continuously causes slight adjustments of the valve plug 70, increasing or decreasing the amount of air released at the vent 58 and thus continuously regulating the pressure in the delivery pipe 10 and at the delivery nozzle 8. This regulation adapts the device for operation on cloth of diifcrent thicknesses or diiferent degrees of porosity. If necessary or desirable the adjusting knob 16 of pressure adjusting valve 14 will be moved to adjust the device for operations on difierent cloth. Upon the arrival of a butt seam between the nozzles 8 and 20 the amount of air passing through the web is suddenly increased and this pulse of increased pressure passes through the recovery pipe 22 to the diaphragm 34 of control switch 30, lifting rod 36 into contact with contact 43 and closing the circuit to control the operation being performed on the web.

In the modification, Figs. 6 and 7, air under pressure is supplied at to a pressure adjusting valve 102 which may be identical with the valve 14 of the device of Fig. 1. From the valve 102 the air at adjusted pressure passes through Ts 104, 106 and 108 into a delivery pipe 110 having a delivery nozzle 112. In this modification no recovery nozzle isemployed. Instead, the pressure responsive control switch 114 is connected directly to the delivery pipe 110, the T 108 being provided for this purpose.

Likewise, the control port of the pressure regulating valve 116 is connected directly to the delivery pipe 110 through T 106 and the pipe 118. The pressure regulating valve 116 is identical in construction with the pressure regulating valve 50 of Fig. 1. The pressure responsive control switch 114 is substantially the same as the control switch 30 of the device of Fig. 1 except that it is arranged to close the circuit upon a decrease instead of an increase of pressure. As shown in Fig. 6, the switch contact rod 120 carries a contact 122 normally spaced from the fixed contact 124 on insulating block 126. When, however, a seam arrives at the delivery nozzle 112 the rate of flow of air through the cloth suddenly increases, lowering the pressure in delivery pipe 110 and on the lower face of the diaphragm of switch 114, causing contacts 122 and 124 to be brought together to close the circuit for control of the operation on the cloth.

Desirably in this modification the web 2 is passed directly in contact with the delivery nozzle, as is shown in Fig. 7.

Variations of pressure in the pipe 110 due to differences in the thickness of the cloth in the web are transmitted (through pipe 118) to the pressure regulating valve 116. As in the case of valve 50 of the device of Fig. 1, pressure regulating valve 116 thus is continually adjusted to regulate the pressure in the delivery noz- Zle 112.

In the modification of Fig. 8, again no recovery nozzle is employed, but, in this modification instead of air under pressure, a vacuum is applied at the delivery nozzle 128. A pressure responsive control switch 130, similar in function to the switch 30 of Fig. 1, is connected directly to the delivery pipe 132 through T 134. A vacuum breaking and regulating device 136 is connected to the delivery pipe 132 through T 138. The device 136 opens when the pressure in the delivery pipe 132 falls below a predetermined value, due to variation of porosity of web 2, to admit air to the delivery pipe and reestablish the desired pressure level. The device 136 may be adjusted by turning the knob 140 to provide the desired low pressure level in delivery pipe 132. As appears in Fig. 9, the control switch is generally similar to the switch 30 of Fig. 1, having a diaphragm 144, and contact rod 146 resting thereon. The spring 142 is located below the diaphragm.

In the operation of the modification of Fig. 8, web 2 is drawn into contact wtih the opening of the delivery nozzle 128. The reduced air pressure against the lower face of the cloth at the nozzle 128 causes a flow of air downwardly through the cloth. Relatively minor fluctuations in the porosity of the cloth are taken care of by the vacuum breaking device 136, as described. When, however, a seam arrives at the nozzle, the flow through the cloth greatly increases, increasing the pressure at the tee 134 sufiiciently to raise the diaphragm 144 and cause contact rod 146 to move upwardly to close the switch 130 and thus control the operation on the web to accommodate the passage of the seam.

I claim:

1. An apparatus for detecting the arrival of a scam in a traveling web of cloth at a station at which an operation is performed on the cloth and for thereupon conttollingsaid operation, comprising a delivery nozzle'for directing a stream of gas against one face of thew'eb, a recovery 'nozzle on the other side of the Web opposite the delivery nozzle, means for regulating the pressure of said stream in accordance with variation of pressure in said recovery nozzle, and means responsive to substantial increase of pressure in said recovery nozzle for controlling said operation.

2. An-apparatus for'detecting the arrival of a butt scam in a traveling web of cloth atv a station at which an operation is performed on the cloth, and for thereupon controlling said operation comprising a delivery nozzle for directing a stream of air against one face of the web, means for supplying air under pressure to said delivery nozzle, a recovery nozzle on the other side of the web opposite the delivery nozzle, means for regulating the pressure of said supplied air in accordance with variation of air pressure in said recovery nozzle, and means responsive to substantial increase of air pressure in said recovery nozzle for controlling said operation.

3. An apparatus for detecting the arrival of a butt scam in a traveling web of cloth at a station at which an operation is performed on the cloth and thereupon controlling said operation, comprising means for supplying air under pressure, a valve for adjusting said pressure, a delivery nozzle on one side of the web for directing a stream of air from said adjusted pressure supply against one face of said traveling web, a recovery nozzle on the other side of the web for receiving air passing through the web from said stream, a sensing diaphragm having one side in communication with the air within said recovery nozzle, an electrical switch connected to control said operation and adapted to be operated between open and closed position by movement of said diaphragm, a relief valve in said air supply, means responsive to fluctuations in air pressure within said recover nozzle to adjust said relief valve to lower the pressure of said air supply upon increase of air pressure in said recovery nozzle and to increase the pressure of said air supply upon decrease of air pressure in said recovery nozzle, and an orifice connecting said air supply to said recovery nozzle.

4. An apparatus for detecting the arrival of a seam in a traveling web of cloth at a station at which an operation is performed on the cloth, comprising means for directing a stream of gas against one face of the traveling web, means for regulating the pressure of said stream in accordance with variations in the gas permeability of the portion of the web at said station and means responsive to a substantial change in the gas permeability of the web passing said station for controlling said operation.

5. An apparatus for detecting the arrival of a butt seam in a traveling web of cloth at a station at which an operation is performed on the cloth, comprising means adjacent said station for unbalancing the air pressure on the opposite faces of the traveling web, means for regulating the amount of said unbalance in accordance with variations in the air permeability of the traveling web, and means responsive to a substantial increase in the air permeability of the traveling web for controlling said operation.

6. An apparatus for detecting the arrival of a butt scam in a traveling web of cloth at a station at which an operation is performed on the cloth, comprising means adjacent said station for directing a stream of air against one face of the traveling web, means for regulating the pressure of said stream in accordance with variations in the air permeability of the traveling web, and means responsive to a substantial increase in the air permeability of the traveling web for controlling said operation.

7. An apparatus for detecting the arrival of a portion of abnormal air permeability in a traveling air permeable web at a station at which an operation is performed on the web, comprising means adjacent said station for unbalancing the air pressure on the opposite faces of the traveling web by applying sub-atmospheric air pressure against one face of the traveling web, means for regulating said unbalance in accordance with variations in the air permeability of the traveling web and means responsive to abnormal change in said unbalance upon approach to the station of a web portion of abnormal air permeability for controlling said operation.

8. An apparatus for detecting the arrival of a portion of abnormal gas permeability in a traveling gas permeable web at a station at which an operation is performed .on the web, comprising means adjacent said station for directing a stream of air against one face of the traveling web, means responsive to variation of air pressure at the face of the web opposite said station for regulatingv the pressure of said stream in accordance with said variation, and means responsive to a substantial change in the air pressure at the face of the web opposite said stream for controlling said operation.

9. An apparatus for detecting the arrival of a seam in a traveling web of cloth at a station at which an operation is performed on the cloth, and for thereupon controlling said operation, comprising a delivery nozzle for directing a stream of air against one face of the web, a recovery nozzle on the other side of the web opposite said delivery nozzle, an orifice connecting the delivery nozzle to the recovery nozzle, and means responsive to substantial increase of air pressure in said recovery nozzle for controlling said operation.

10. An apparatus for detecting the arrival of a butt seam in a traveling web of cloth at a station at which an operation is performed on the cloth and for thereupon controlling said operation, comprising a delivery nozzle adjacent said station for applying a sub-atmospheric pressure to one face of the web to unbalance the air pressure on the opposite faces of the traveling web, means for regulating the amount of said unbalance in accordance with variations in the air permeability of the traveling web, and means responsive to a substantial increase in the air permeability of the traveling web for controlling said operation.

11. An apparatus for detecting the arrival of a butt seam in a traveling web of cloth at a station at which an operation is performed on the cloth, and for thereupon controlling said operation, comprising a delivery nozzle adjacent said station for applying a sub-atmospheric pressure to one face of the web to unbalance the air pressure on the opposite faces of the traveling web, means for regulating the amount of said unbalance in accordance with variations of air permeability of the traveling web, means for regulating the amount of said unbalance by varying said sub-atmospheric pressure in accordance with variation of the rate of flow of air through the web into the delivery nozzle due to variation of air permeability of the traveling web, and means responsive to substantial increase of in the air permeability of the traveling web for controlling said operation.

12. An apparatus for detecting in a traveling gas permeable web the approach of a web portion of abnormal gas permeability to a station at which an operation is performed, comprising means adjacent said station for unbalancing the gas pressure on the opposite faces of the traveling web, means for regulating the amount of said unbalance in accordance with variation in the gas permeability of the traveling web, and means responsive to abnormal change in said unbalance upon approach to the tion of abnormal air permeability in a traveling air-permeable Web at a statition at which an operation is performed on the Web, comprising means adjacent said station for unbalancing the air pressure on the opposite faces of the traveling Web, means for regulating the amount of said unbalance in accordance with variation in the air permeability of the traveling Web, and means responsive to abnormal change in said unbalance upon approach to the station of a web portion of abnormal air permeability for controlling said operation.

14. An apparatus for detecting the arrival of a scam in a traveling Web of cloth at a station at which an operation is performed on the cloth, comprising means for directing a stream of gas against one face of the traveling web, means for regulating the pressure of said stream in accordance with variation in the gas permeability of the portion of the Web at said station and means re- 0 sponsive to a substantial decrease in the pressure of said stream, due to increase in the gas permeability of the web passing said station, for controlling said operation.

References Cited in the file of this patent UNITED STATES PATENTS 561,772 Dexter June 9, 1896 1,065,576 Amet June 24, 1913 1,322,506 Austin Nov. 25, 1919 1,911,259 Bergoin May 30, 1933 1,964,943 Harris et al. July 3, 1934 2,042,695 Zofzik June 2, 1936 2,317,921 Leach Apr. 27, 1943 2,375,451 Waters May 8, 1945 2,588,329 Sillers Mar. 4, 1952 2,814,487 Medkefi Nov. 26, 1957 2,843,863 Weisz July 22, 1958 2,853,574 Quirk Sept. 23, 1958 FOREIGN PATENTS 706,245 Great Britain Mar. 24, 1954 

